Bypass that lint

src/distance.rs

@@ -116,6 +116,7 @@ pub static AIRPORTS_MAP: Lazy<HashMap<&'static str, Airport>> = Lazy::new(|| {
 ///
 /// assert_eq!(distance.round() as i64, 95);
 /// ```
+#[allow(clippy::must_use_candidate)]
 pub fn haversine(lat1: f64, lon1: f64, lat2: f64, lon2: f64) -> f64 {
     let r = 6371e3;
     let φ1 = (lat1 * PI) / 180_f64;